/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Rhino code, released
 * May 6, 1999.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1997-1999
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Norris Boyd
 *   Igor Bukanov
 *   Bob Jervis
 *   Roger Lawrence
 *   Mike McCabe
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License Version 2 or later (the "GPL"), in which
 * case the provisions of the GPL are applicable instead of those above. If
 * you wish to allow use of your version of this file only under the terms of
 * the GPL and not to allow others to use your version of this file under the
 * MPL, indicate your decision by deleting the provisions above and replacing
 * them with the notice and other provisions required by the GPL. If you do
 * not delete the provisions above, a recipient may use your version of this
 * file under either the MPL or the GPL.
 *
 * ***** END LICENSE BLOCK ***** */

package org.mozilla.javascript;

import org.mozilla.javascript.debug.DebuggableScript;

/**
 * This class implements the Function native object. See ECMA 15.3.
 * 
 * @author Norris Boyd
 */
public abstract class NativeFunction extends BaseFunction {

  /**
   * 
   */
  private static final long serialVersionUID = 4315215418133888996L;

  /**
   * @param indent
   *          How much to indent the decompiled result
   * 
   * @param flags
   *          Flags specifying format of decompilation output
   */
  @Override
  final String decompile(int indent, int flags) {
    String encodedSource = getEncodedSource();
    if (encodedSource == null)
      return super.decompile(indent, flags);
    else {
      UintMap properties = new UintMap(1);
      properties.put(Decompiler.INITIAL_INDENT_PROP, indent);
      return Decompiler.decompile(encodedSource, flags, properties);
    }
  }

  @Override
  public int getArity() {
    return getParamCount();
  }

  public DebuggableScript getDebuggableView() {
    return null;
  }

  /**
   * Get encoded source string.
   */
  public String getEncodedSource() {
    return null;
  }

  protected abstract int getLanguageVersion();

  @Override
  public int getLength() {
    int paramCount = getParamCount();
    if (getLanguageVersion() != Context.VERSION_1_2)
      return paramCount;
    Context cx = Context.getContext();
    NativeCall activation = ScriptRuntime.findFunctionActivation(cx, this);
    if (activation == null)
      return paramCount;
    return activation.originalArgs.length;
  }

  /**
   * Get number of declared parameters and variables defined through var
   * statements.
   */
  protected abstract int getParamAndVarCount();

  /**
   * Get number of declared parameters. It should be 0 for scripts.
   */
  protected abstract int getParamCount();

  /**
   * Get parameter or variable const-ness. If
   * <tt>index < {@link #getParamCount()}</tt>, then return the const-ness of
   * the corresponding parameter. Otherwise return whether the variable is
   * const.
   */
  protected boolean getParamOrVarConst(int index) {
    // By default return false to preserve compatibility with existing
    // classes subclassing this class, which are mostly generated by jsc
    // from earlier Rhino versions. See Bugzilla #396117.
    return false;
  }

  /**
   * Get parameter or variable name. If
   * <tt>index < {@link #getParamCount()}</tt>, then return the name of the
   * corresponding parameter. Otherwise return the name of variable.
   */
  protected abstract String getParamOrVarName(int index);

  public final void initScriptFunction(Context cx, Scriptable scope) {
    ScriptRuntime.setFunctionProtoAndParent(this, scope);
  }

  /**
   * @deprecated Use {@link BaseFunction#getFunctionName()} instead. For
   *             backwards compatibility keep an old method name used by Batik
   *             and possibly others.
   */
  @Deprecated
  public String jsGet_name() {
    return getFunctionName();
  }

  /**
   * Resume execution of a suspended generator.
   * 
   * @param cx
   *          The current context
   * @param scope
   *          Scope for the parent generator function
   * @param operation
   *          The resumption operation (next, send, etc.. )
   * @param state
   *          The generator state (has locals, stack, etc.)
   * @param value
   *          The return value of yield (if required).
   * @return The next yielded value (if any)
   */
  public Object resumeGenerator(Context cx, Scriptable scope, int operation,
      Object state, Object value) {
    throw new EvaluatorException("resumeGenerator() not implemented");
  }
}
